1. Field of the Invention
The present invention relates to a cryptographic communication method for use in cryptographic communication of information among plural CPUs through communication line and more particularly to a chaos cryptographic communication method and chaos cryptographic communication system capable of achieving robust, highly reliable cryptographic communication which prevents illegal access so as to ensure only legal access.
2. Description of the Related Art
Establishment of social system having robustness and high reliability against every kind of disturbance has been demanded in transportation industries related to, for example, automobile, train, airplane and the like.
To meet such demands, it can be considered to build up a system based on a result of logical operation or linear operation with relatively simple one-to-one correspondence. However, it has been recognized that if the system is built up based on such philosophy, a sufficient reliability cannot be always secured in industry concerning human life. Digital computer mentioned here refers to a machine which executes repetitive jobs faithfully according to a program by logical operation of binary code. Although the digital computer is believed to have a high robustness because it is capable of coping with a large amount of data, basically this is a logical operating machine with one-to-one correspondence. Thus, it is very weak against disturbance. Computer runaway and infection by virus are examples indicating that weakness.
For the reason, it has been demanded strongly to build up a robust, highly reliable and practical system capable of ensuring only a legal access while protecting from illegal access.